Automobiles, trucks, buses, off-road and construction vehicles, aircraft and light rail vehicles commonly use disk brakes. Disk brakes utilize a disk which turns with the wheel of the vehicle. When the brakes are applied, stationary pads are pressed against the rotor through hydraulic pressure by a brake caliper. The frictional forces between the brake pads and the rotor slow or bring the vehicle wheel to a stop.
A problem commonly associated with disk brakes is that unwanted noise and vibration are generated during the braking process. Numerous attempts have been made to reduce, or prevent, the unwanted noise and vibration by adding separate components to the rotor after it has been cast. For example, U.S. Pat. No. 5,855,257 provides for a ring damper affixed around the periphery of a rotor after the rotor is cast. The ring damper is designed to be located in the groove formed by the two joined disk plates. The ring is held in place by the groove and is alleged to absorb vibration, and reduce noise, from the rotor during braking.
U.S. Pat. No. 3,425,523 teaches a ventilated rotor with a vibration dampener. The dampener is constructed of wire and has a looped portion with two legs integrally formed with the loop. The dampener is removably disposed in one or a plurality of locations in the radially extending open ended apertures of a rotor after the rotor is cast.
U.S. Pat. No. 3,292,746 provides for a circular vibration dampening member having loop portions extending into spaces between circumferentially spaced, radially extending walls. The loop portions are a separate component added to the completed rotor after casting.
Rotors, such as those described above, are often manufactured using a sand core and a mold in a process well known to those skilled in the art. The dampener is added to the rotor in a manual step after it is taken from the mold and the sand core is removed.
Therefore, it would be desirable to have at least one dampening structure within a sand core where that sand core is used to form a part. After the part is cast about the sand core, the sand core is removed and the dampening structure is left behind in the part.